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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
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package com.oracle.svm.core.jvmstat;

import java.nio.ByteBuffer;

import jdk.graal.compiler.word.Word;
import org.graalvm.word.Pointer;

import com.oracle.svm.core.jdk.DirectByteBufferUtil;
import com.oracle.svm.core.memory.NativeMemory;
import com.oracle.svm.core.nmt.NmtCategory;

/**
 * Allocates a buffer with a minimal size that only contains the performance data header (see
 * {@link PerfMemoryPrologue}).
 */
public class CHeapPerfMemoryProvider implements PerfMemoryProvider {
    private Pointer memory;

    @Override
    public ByteBuffer create() {
        int size = PerfMemoryPrologue.getPrologueSize();
        memory = NativeMemory.calloc(size, NmtCategory.JvmStat);
        return DirectByteBufferUtil.allocate(memory.rawValue(), size);
    }

    @Override
    public void teardown() {
        if (memory.isNonNull()) {
            NativeMemory.free(memory);
            memory = Word.nullPointer();
        }
    }
}
